Yarn tensioning device for double twist spindles



Dec. 27, 1966 HIDEO YANOBU 3,

YARN TENSIONING DEVICE FOR DOUBLE TWIST SPINDLES Filed Nov. 25, 1965 2 Sheets-Sheet l FIG.3

INVENTOR. HIPEO YHNO'BU Dec. 27, 1966 HlDEO YANOBU 3,293,839

YARN TENSIONING DEVICE FOR DOUBLE TWIST SPINDLES Filed Nov. 23. 1965 2 Sheets-Sheet 2 FIG.7

HifDEO YHNOBu INVENTOR.

United States Patent 3,293,839 YARN TENSIONING DEVICE FOR DOUBLE TWIST SPINDLES Hideo Yanobu, Kyoto-shi, Kyoto-fu, Japan, assignor to Murata Kikai Kabushiki Kaisha, Kyoto-shi, Kyoto-fu, Japan, a joint-stock company of Japan Filed Nov. 23, 1965, Ser. No. 509,268 Claims priority, application Japan, June 4, 1965, 40/ 45,040 5 Claims. (Cl. 57-5836) This invention relates to double twist spindles and more particularly to a new yarn tensioning device installed in the upper end of bobbins of double twist spindles to apply necessary tension constantly to the yarn.

In a double twist spindle, when a synthetic filament yarn, such as filament yarn of polyamides (nylon), polyesters (tetron), and polyvinyl alcohol (vinylon), is to be twisted, the problem requiring the most careful consideration is that of how to apply constant tension to the yarn. If there are fluctuations in the yarn tension, uniform twisting cannot be obtained. Consequently, the yarn quality will, of course, be lowered, and adverse effects will be imparted also to the processes subsequent to twisting.

Ordinarily, these synthetic filament yarns which are twisted in double twist spindles are each composed of from 20 to 30 filaments and have the common disadvantages of having weak resistance to heat and being readily charged electrostatically by friction. Accordingly, extreme care is required also in applying the necessary tension to the yarn during twisting, and occurrences such as the application of a high tension at one time must be absolutely avoided.

More specifically, defective operational occurrences such as filament separation due to electrostatic charges, formation of large and small loops by one or more filaments, and filament breakage, which occurrences arise when the necessary tension is applied at one time, must be absolutely prevented. In addition, since individual filaments can be considered to contain latent tension deviations from the time of spinning, although these deviations are limited, it is not easy to overcome these adverse conditions and apply constant tension without deviations to the yarn.

Furthermore, in known miniature tensioning devices of the instant type, because of unraveling resistance of the pirn and other causes, sliding and other moving parts of the tensioning device have had a tendency to jump with the result that the yarn passing immediately there after is passed in a state of almost no tension, whereby great deviations in tension are caused.

It is a general object of the present invention to overcome these difliculties.

More specifically, an object of the present invention is to provide a yarn tensioning device for double twist spindles which makes possible the application of suitable and necessary tension to the yarn in a stepwise manner, increasing the tension a little at a time, and which is installed compactly in a limited space.

According to the present invention, briefly stated, there is provided a yarn tensioning device for double twist spindles comprising, essentially, a pair of yarn tensioning members having mutually spaced apart and meshing projections and concavities between which yarn to be tensioned is passed in a zig-zag path in contact with the extremities of the projections, said projections and concavities progressively increasing in length in their dispositional sequence in the direction of travel of the yarn, and means of adjusting the depth of enmeshment of the projections and cavities of the two tensioning members, said members and said means being compactly enclosed within an entry cone cap disposed at the top of a bobbin on a double twist spindle.

The nature, principle, and details of the invention will be more clearly apparent from the following detailed description of a preferred embodiment of the invention and modifications thereof, when read in conjunction with the accompanying drawings in which like parts are designated by like reference numerals, and in which:

FIG. 1 is an elevational sectional view showing the general arrangement and construction of a double twist spindle of the type to which the present invention is applicable;

FIG. 2 is a relatively enlarged, elevational sectional view showing the embodiment of the invention in installed state in the entry cone at the upper part of a bobbin mounted on the spindle shown in FIG. 1;

FIG. 3 is an exploded perspective view, with a part cut away, showing the essential inner parts of the yarn tensioning device shown in FIG. 2;

FIG. 4 is a perspective view showing the outer appearance of the entry cone at the upper part of the spindle with the yarn tensioning device of the invention installed therein; and

FIGS. 5, 6, and 7 are elevational sectional views, show ing different examples of modification of the tensioning members for applying tension in the device according to the invention.

Referring first to FIGS. 1 and 2, the yarn tensioning device embodying the invention is installed compactly within a tensioning device main structure 3 constituting an entrance cone and upper cap of a bobbin 1 which supports a yarn cop or package 2a of yarn 2 prior to twisting wound thereabout, and which is fitted on a double twist spindle of known type.

When the take-up operation begins, the yarn 2 is led, as it revolves in its unraveling direction, through an upper guide 4 on the top of the tensioning device main structure 3 and is tensioned and, at the same time, prepared by tensioning members 5 and 6. The yarn thereupon assumes a twisted state and is led out through a lower guide 7.

A ring 8 is placed to rest over the yarn 2 around the outer conical part of the main structure 3 to govern the movement and configuration of the unraveling yarn 2 with minimum resistance. A ball 9 having a similar function as the ring 8 is placed to rest on the entering yarn 2 in a flared part at the upper end of the guide bore 4a of the upper guide 4. The ball 9 and ring 8 impart temporary tension to the yarn, and depending on the nature of the yarn, winding speed, and other conditions, only one or the other may be used, or both may not be used in some cases.

The tensioning members Sand 6 have mutually opposed surfaces with teeth-like horizontal projections, as viewed in side elevation, vertically spaced at suitable intervals so that the projections of one member can mesh loosely into corresponding concavities in the other member. The lengths of these projections progressively increase from the uppermost to the lowermost projection so as to apply tension in a stepwisely progressive manner to the yarn.

The tensioning member 5 is fixed to a fixed holder 11 having a threaded hole 10 and secured by a screw 12 against the blind end wall of a horizontal hole 15 formed in the main structure 3. The fixed holder 11 and tensioning member 5 are provided with flat vertical sides parallel to the axis of the hole 15.

The other tensioning member 6 is fixedly fitted at its base end to a hole 14a in a sliding holder 14 having a deep longitudinal, vertical slot 13 flanked by yoke-like projections 13a which are adapted to slide between the flat vertical sides of the fixed holder 11 and tensioning member 5 and the wall of the hole 15. The sliding holder 14, together with the tensioning member 6 thus fixed thereto, is urged toward the tensioning member 6 by one end of a compressed spring 16, the compressive force of which is regul able by a cap screw 17 against which the other end of the spring 16 is seated, and which is engaged with screw threads tapped on the bore of the hole 15.

The cap screw 17 is provided with a slot 18 for turning by means of a screw driver. Thus, the tension applied to the yarn can be adjusted by turning the cap screw 17 and regulating the compressive force of the spring 16, suitable tension being maintained by a balance between the compressive force of the spring 16 and the reaction due to bending of the yarn as it passes through between the tensioning members 5 and 6.

Furthermore, the tensioning device main structure 3 has in its side semicircular cutouts 19 exposing a part of the sliding holder 14, whereby, by manually pushing the sliding holder against the force of the spring 16, it is possible in a simple manner to pass the yarn through the device in the direction of the arrow shown in FIG. 4 when the yarn is being threaded through the device.

As a precaution to prevent the passing yarn from sliding off the tensioning members 5 and 6 when these members are mutually emmeshed, the working edges 5a and 5b of the projections of the tensioning members 5 and 6 are formed with a concavity as shown in FIG. 3.

A further advantageous feature of the tensioning device of the invention is that the fixed holder 11 and sliding holder 14 for securely holding the tensioning members 5 and 6 relative to the main structure 3 can be disassembled and taken out in a simple manner by merely unscrewing the screw 12 and the cap screw 17. Therefore, depending on the operational conditions of the nature of the yarn, its thickness, and its speed, the tensioning members 5 and 6 can be freely and suitably selected from among those of various configurations as, for example, the twoto-three projection combination shown in FIG. 5, the three-to-four projection combination shown in FIG. 6, or a combination of members whose projections vary ourvilinearly in length as indicated in FIG. 7 in contrast to the proportional linear increase in said length as indicated in FIGS. 5 and 6.

As described above, the present invention provides a yarn tensioning device of extremely compact construction adapted to be installed in the upper end part of bobbins of double twist spindles, in which yarn tensioning device the required yarn tension is applied progressively in a stepwise manner to the yarn, ballooning of the yarn is suppressed, and the tension of the yarn after the application thereon of the primary tension is constantly maintained, whereby generation of electrostatic charge, filament separation, formation of loops, and other undesirable occurrences of synthetic-fiber filament yarn due to abrupt application of tension can be completely eliminated.

Furthermore, in the yarn tensioning device according to the invention, since the tensioning members 5 and 6 are mutually meshed in -a manner to cause the bending of the yarn to increase progressively, the tension is gradually reduced and gradually applied even when these members are caused to jump. Accordingly, portions of the yarn passing through in a state of no tension, as often occur in the case of known tensioning devices, are almost completely eliminated.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention as set forth in the appended claims.

What I claim is:

1. A yarn tensioning device for double twist spindles comprising -a pair of mutually opposed and cooperatively operating yarn tensioning members for resistively clamping therebetween yarn thereby to impart tension to the yarn -as it travels therebetween, each of said tensioning members having a given number of tooth-like projections and recesses in alternate arrangement in the direction of yarn tr-avel which are loosely enmeshable with corresponding like recesses and projections of the other said tensioning member, whereby the yarn is caused to pass through a zig-zag pathin contact with and around the extrernities of the projections, said projections and recesses progressively increasing in length and depth, respectively, in their dispositional sequence in the direction of yarn travel thereby to impart a required tension to the yarn in a stepwise, progressively increasing manner, and tension regulating means to vary 'adjustably the distance between the two tensioning members and thereby the degree of mutual enmeshment of their projections and recesses thereby to vary the tension applied to the yarn.

2. The yarn tensioning device for double twist spindles according to claim 1, wherein said tensioning members and tension regulating means are completely housed within a main structure of the yarn tensioning device, said main structure constituting a yarn entrance cap mounted on the top of a bobbin which carries a package supplying said yarn and is mounted on a double twist spindle.

3. The yarn tensioning device for double twist spindles according to claim 1, wherein the pair of tensioning members and at least a part of the tension regulating means are readily replaceable by pairs having different numbers of tooth like projections and corresponding recesses.

4. The yarn tensioning device for double twist spindles according to claim 3, wherein one of the tensioning members is fixed to and held by a movable holder, and said main structure of the yarn tensioning device is provided in its lateral side with cutout parts exposing said movable holder whereby said movable holder can be manually manipulated to facilitate passage of the yarn when said yarn is being threaded through the yarn tensioning device. 5. The yarn tensioning device for double twist spindles according to claim 4, wherein the tension regulating means comprises an adjusting screw, the screw threads of which are engaged with threads tapped in the device main structure, and a spring interposed between the adjusting screw and the movable holder and imparting a force to urge the movable holder, and therefore the movable tensioning member, toward the fixed tensioning member, whereby adjusting movements of the adjusting screw cause corresponding variations in said force and, accordingly, corresponding variations in tension applied to the yarn.

References Cited by the Examiner UNITED STATES PATENTS 1,142,531 6/1915 Royle 242153 2,615,656 10/1952 Str-ake 242-154 2,776,805 1/1957 Klein 242-154 2,795,924 6/ 1957 Borges 242-154 X 2,864,566 12/1958 Klein 242-l53 2,921,755 1/ 1960 Borges 242-154 3,001,356 9/1961 Klein 5758.84 3,087,689 4/1963 Heim 242-454 FRANK I. COHEN, Primary Examiner.

D. WA Ex m ner; 

1. A YARN TENSIONING DEVICE FOR DOUBLE TWIST SPINDLES COMPRISING A PAIR OF MUTUALLY OPPOSED AND COOPERATIVELY OPERATING YARN TENSIONING MEMBERS FOR RESISTIVELY CLAMPING THEREBETWEEN YARN THEREBY TO IMPART TENSION TO THE YARN AS IT TRAVELS THEREBETWEEN, EACH OF SAID TENSIONING MEMBERS HAVING A GIVEN NUMBER OF TOOTH-LIKE PROJECTIONS AND RECESSES IN ALTERNATE ARRANGEMENT IN THE DIRECTION OF YARN TRAVEL WHICH ARE LOOSELY ENMESHABLE WITH CORRESPONDING LIKE RECESSES AND PROJECTIONS OF THE OTHER SAID TENSIONING MEMBER, WHEREBDY THE YARN IS CAUSED TO PASS THROUGH A ZIG-ZAG PATH IN CONTACT WITH AND AROUND THE EXTREMITIES OF THE PROJECTIONS, SAID PROJECTIONS AND RECESSES PROGRESSIVELY INCREASING IN LENGTH AND DEPTH, RESPECTIVELY, IN THEIR DISPOSITIONAL SEQUENCE IN THE DIRECTION OF YARN TRAVEL THEREBY TO IMPART A REQUIRED TENSION TO THE YARN IN 